A phrase used to describe your best drinking buddy/wingman to a girl at a bar/club. As you introduce him to her as your ace in the club, you should always spill a bit of your drink on him. This shows her that while he may be an ace, you're still king.

You to hottie: "This is Tony, my ace in the club."
Tony to you: "Dude, you spilled some of your martini on me."
Hottie to you: "Let's go have sex!"